Many radio-frequency (RF) communication systems transmit information within multiple frequency ranges, or “channels,” of the RF spectrum simultaneously. As a result, a device attempting to receive and process information transmitted in a particular channel may need to isolate signals propagating at frequencies within the relevant channel for further processing and may discard signals propagating outside the relevant channel. Consequently, filtering is a common operation in multi-frequency communication systems.
In many applications, the isolated signal is also amplified to prepare the signal for further processing. Amplification may induce non-linearity in the isolated signals, particularly as the level of amplification is adjusted to accommodate input signals of varying strength. This non-linearity may, in turn, lead to deteriorated performance in the overall system.